Balance-staff for watches.



A. E, HUR-WITZ & C. W. GOODMAN.

BALANCE STAFF FOR WATCHES.

APPLICATION FILED JULY3, 1913.

Patented Dec. 2, 1913.

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UNITED STATES PATENT OFFICE.

AARON E. HURWITZ AND CHARLES W. GOODMAN, OF PORTLAND, OREGON.

BALANCE-STAFF FOR WATCHES.

Specification of Letters Patent.

Patented Dec. 2, 1913.

AppIication filed July- 3, 1913. Serial No. 777,311.

. balance staffs for Watches.

One object of the invention is to provide a balance staff having an improved means for attaching the balance wheel thereto whereby the staff may be readily removed when necessary and replaced by a new staff Without injuring the balance wheel and without requiring truing or poising, tiniing and other work usually necessary in removing and resetting the ordinary form of balance staff.

Another object is to provide a balance stafi' which is simple, strong and durable in construction, efficient and reliable in operation and on which the roller plate may be arranged to bring the roller jewel in proper position with respect to the escapement without resetting the roller jewel.

With these and other objects in view, the invention consists of certain novel features of construction, and the combination and arrangement of parts as will be more fully clescribed and claimed.

In the accompanying drawings; Figure 1 is a central vertical section of a balance wheel showing the same applied to our improved balance staff, parts of the latter being shown in section; Fig. 2 is a side View of the staff with the wheel clamping nut thereof removed; Fig. 8 is a central vertical section of the staff Fig. 4 is a similar view of the balance Wheel clamping nut; Fig. 5 is a top plan or upper end view of the nut; Fig. 6 is a bottom plan or lower end view thereof; Figs. 7 and 8 are respectively side and end views of the key for screwing the clamping nut on and off the balance staff.

ur improved balance staff comprises a body portion 1 on which is formed a smooth balance wheel engaging surface or rest 2 below which the body of the staff is threaded for a suitable distance as shown at 3. Above the balance wheel rest 2 is formed an annular flange or shoulder 4 against which the balance wheel B is secured by a suitable clamping means hereinafter described. Above the flange or shoulder 4 is formed the usual rest or surface 5 to which the hair spring (not shown) is secured in the usual manner. Above the hair spring rest 5 is formed the upper balance pivot 6 which is also of the usual construction. Below the threaded portion 3, the balance staff is reduced and tapered as at 7 to receive the roller plate P which is driven onto the reduced portion 7 of the staff in the usual manner until it is disposed immediately below and in close engagement with the enlarged threaded portion 3 of the staff and the lower end of the nut as shown. The roller jewel plate P may be of the usual construction and carries the usual roller jewel R with which the escapement is engaged. On the lower end of the reduced portion 7 of the balance staff is formed the usual lower pivot S.

Adapted to be screwed onto the threaded portion 3 of the balance staff is a balance wheel clamping nut 9 the outer surface of which preferably tapers slightly from its upper toward its lower end and in the lower end of which is formed a series of notches or recesses 10 with which are adapted to be engaged lugs 11 formed on the outer end of a key 12 which may be employed for screwing the nut 9 onto and off from the threaded portion 3 of the staff as will be readily understood.

In assembling the parts or in setting a balance staff, the latter is inserted through the balance wheel from the upper side or above the same until the stop flange or shoulder 4 comes into engagement with the wheel after which the clamping nut 9 is screwed onto the threaded portion 3 of the staff and into engagement with the lower side of the wheel thereby firmly clamping the latter between the nut and the flange 4 in which position the balance wheel is securely held without being keyed, pinned or otherwise secured to the staff. The plate P is then driven onto the lower tapered portion 7 of the staff and into contact with the lower end of the threaded portion 3 and the lower end of the nut 9, which latter is therefore and thereby prevented from accidentally unscrewing or loosening to such an extent that the balance wheel B will become loose on the staff. By thus fastening the balance wheel any danger of injuring the latter is obviated and the necessity of truing or poising, timing or otherwise adjusting the balance wheel is eliminated, thereby saving a great deal of the time, labor and trouble usually required in setting the ordinary form of balance staff and wheel. In thus fastening the balance wheel it will also be seen that if the balance staff should be broken or it should become necessary to re move the same for any reason, this operation may be readily accomplished by simply un screwing the nut 9 and drawing the staff out from the top side of the balance wheel thereby obviating the necessity of undercutting or driving out the old staff.

From the foregoing description taken in connection with the accompanying drawings, the construction and operation of the invention will be readily understood without requiring a more extended explanation.

Various changes in the form, proportion, and the minor details of construction may be resorted to without departing from the principle or sacrificing any of the advantages of the invention as claimed.

Having thus described our invention, what we claim is:

The combination with a balance wheel and a roller plate; of a balance staff having pivots at its extremities, a spring rest below the uppermost pivot, a flange below the rest, a surface below and of less size than the flange for entering the hole in the wheel, a reduced and threaded portion below said surface, and a still further reduced and tapered portion below the threaded portion, said tapered portion being adapted to frictionally enter the hole in the plate; and a nut of the same length as said threaded portion, the part-s being assembled substantially as hereinbefore described.

In testimony whereof we have hereunto set our hands in presence of two subscribing witnesses.

AARON E. HURl VITZ. CHARLES N. GOODMAN. lVitnesses DAVID M. HoLnRoon, GILBERT E. HAMAKER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

